Answer:
D. \(3a^4b\)
Step-by-step explanation:
We have: \(a.3a^3b\) in order to simplify this expression, we have to apply the rule of the exponents.
This rule says that:
\(a^b.a^c=a^(^b^+^c^)\)
If you have the same base, the exponents can be added.
We can rewrite the expression \(a.3a^3b\) as \(3(a.a^3)b\)
Then we have:
\(a.a^3=a^1.a^3=a^(^1^+^3^)=a^4\)
Finally:
\(a.3a^3b=3(a^4)b=3a^4b\)
The correct option is D.
